PURPOSE: To obtain a good mold by providing a heating device inside a molding board main body so as to control a temp. at the working face, which is in contact with the sand of the molding board main body.

CONSTITUTION: The temp. sensor 5 and heating device 6 to control a temp. of the working face 1a, which is brought into contact with the sand of the molding board main body through the sensor, are arranged inside the molding main body 1. The heating device 6 is provided with the wind box 8 between the inner face of the molding board main body 1 and the underneath cover plate 7 and a hot air blowing means is provided in the wind box 8. Thus, the temp. of the board working face being in direct contact with sand can be set at any value, accordingly, a sand blending ratio of binder, hardener and sand is made constant even though there exists environment temp. difference, sand is always hardened in the prescribed hardening time.